Fabric tensioning device



Aug. 15, 1961 w. H, IMBODEN 2,995,914

FABRIC TENSIONING DEVICE- Filed June a, 1959 FlE- E. m 27 37 2a 57 2 weINVENTOR. Wa/ter H. /mboaen A TTVRNEY United States Patent sylvama FiledJune 3, 1959, Ser. No. 817,871

7 Clai ms. (Cl. 66-150) The instant invention relates to improved fabrictakeoifs for circular knitting machines and more particularly to suchtake-offs employing a stream of air to tension the fabric, such as astocking, as it is being knit, and after the fabric is pressed off fromthe needles of the knitting machine, to carry it to a collection chamberfrom which it may be discharged into a collection tray or otherreceptacle.

A take-off of the above type and of which the present invention is animprovement is shown, for example, in the co-pending application of St.Pierre et al., Serial No. 500,756, filed April 12, 1955 and in theItalian Patent No. 538,758, issued January 30, 1956 correspondingthereto, referred to hereinafter as the St. Pierre et al. disclosure."In the operation of knitting machines equipped with such take-offsproviding a sufficient volume of air for an adequate tensioning of thefabric it is found preferable at times and essential at other times tointerrupt the air stream. For example, when the fabric is pressed off ofthe needles continuation of the air stream tends to ravel back the lastknitted courses, as the fabric or stocking is whisked away in the airstream, before the cutter of the usual clamp and cutter is able tooperate. Also during the knitting of the heel and toe and particularlythe former it is often found preferable to relieve the tension on thefabric to prevent the enlargement of the loops held on the idle needles.Similarly in the knitting of the makeup courses for a womans stocking,where in order to form a turned welt the yarn is fed alternately toneedles and to dial bits, the air stream exerts a disrupting infiuence.

While in constructions such as described in the St. Pierre et a1.disclosure as well as in other prior suction take-offs means have beenproposed for interrupting the air stream, as for example by shutting offthe suction fan or by closing a valve in the conduit leading to thesuction fan, these proposals have not adequately solved the problem andalso have created problems of their own in that they employ the openingof the door to the collection chamber to operate the suction cutoff orresult in intermittent operation of the fan motor or both.

The principal object of the instant invention is the provision of animproved suction take-off in which the suction fan may be operatedcontinuously and the door to the collection chamber may be maintainedclosed at all times except when a stocking is to be removed but in whichthe air stream leading from the knitting machine and through thecollection chamber may be interrupted at any time desired.

Another object of the invention is the provision of a device as definedabove incorporating pattern controlled means for separately effectingthe opening of the collection chamber door and the interrupting of theair stream.

A still further object of the invention is the provision of such devicecomprising a door for said collection chamber with means for normallyholding it in closed position and a pattern controlled solenoid formoving it to open position. A still further object is the provision insuch mechanism of a port in the collection chamber, providingcommunication with a conduit leading to the suction fan, and a port inthe conduit leading to the atmosphere, and solenoid operated closuremembers for said ports. Another object is the provision of patterncontrolled means for energizing said solenoids for said door and closuremembers.

Briefly described the instant invention resides in a suction take-off ofgenerally conventional type including a tube extending into the needlecylinder and having an open mouth adjacent the knitting point, said tubeleading to and in communication with the collection chamber and a secondtube or conduit leading from the chamber and in communication with theintake side of a suction fan. In accordance with the instant inventionthe chamber has a swingable door, with means, such as a counterweight,for normally maintaining it in closed position. The chamber is furtherprovided with a port opening into the conduit leading to the suction fanthe conduit having a second port leading to the atmosphere. Closures forsaid ports are mounted in a manner whereby upon closing the first portthe second port is opened. The operating means for both the portclosures and also for opening the door comprise solenoids connected intoelectrical circuits energized by the closing of switches by buttons onthe pattern means of the machine.

By the construction described above the air stream created by thesuction means, and which normally passes through the tube and into thecollection chamber and thence through the port in the wall thereof tothe suction fan, may be interrupted at any time desired without thenecessity of opening the door of the collection chamber. Thus bylocating buttons at the appropriate places on the pattern means thesolenoids for the port closures may be operated to close offcommunication between the fan and the collection chamber and tosimultaneously open the conduit to the atmosphere. When a stocking hasreached the collection chamber it may be removed by similarlyinterrupting the air stream and during such interruption energizing thesolenoid for the door to the collection chamber to open said door, thisoperation also being under pattern control.

My invention will be more fully understood and further objects andadvantages thereof will become apparent when reference is made to themore detailed description thereof which is to follow and to theaccompanying drawings in which:

FIGURE 1 is a diagrammatic elevational view with parts in sectionillustrating a device embodying the instant invention; and

FIG. 2 is a sectional view taken on the line 22 of FIG. 1.

Referring now to the drawings and particularly to FIG. 1, there isdiagrammatically shown the knitting head of a conventional circularindependent needle knitting machine, such as a womans hosiery machine,including a cylinder 1, needles 2 slidable in the usual needle slots,sinkers 3 in a sinker-head 4 and a dial 5 carrying the usual dial bits(not shown). Extending interiorly of the needle cylinder 1 is a fabricreceiving tube 6 including a preferably funnel shaped mouth piece 7terminating adjacent the point of formation of the fabric produced onthe machine. Tube 6, preferably made of a clear plastic or the like,extends downwardly suitably for a distance at least equal to the lengthof the fabric to be formed on the machine and leads through a series ofreverse bends 8 to a collection chamber 10 and is secured in relativelyairtight relationship to an upper wall 9 around an opening thereinproviding communication between the interior of the chamber and thetube. The apparatus so far described may be generally the same as thatshown in said St. Pierre et al. disclosure and may include the specificfeatures thereof.

In accordance with the instant invention the collection chamber 10(FIGS. 1 and 2), suitably of cylindrical cross section, includes, inaddition to the upper wall 9, an annular side wall and an opening ordoorway 11 in its as the annular wall of chamber 10. A second arm 23 oflever 14 has its free end pivotally secured as by a pin 16 to one end ofa link 17 the other end of which is pivotally connected as at 18 to anextension 19 of the core member of a pull type solenoid 20. Suspendedfrom the pin 16 is a link 21 supporting a counterweight 22 ofsufl'lcient mass in relationship to the lever arms 13 and 23 to normallymaintain door 12 in a position to close doorway 1-1.

The annular wall of chamber is provided with a port 25 having therein awire mesh screen or the like 26 of suificient porosity to permit thefree flow of air through the port while at the same time preventing astocking or other fabric from being drawn through the port, by thesuction means hereinafter to be referred to. The chamber and associatedelements described above may suitably be made of metal althoughthe'particular materials of which they, as well as other parts, areconstructed is not critical as will be understood.

Exteriorly of the chamber, port 25 is surrounded by a collar 27 defininga seat for a port closure 28 the latter suitably consisting of alightweight fiat sheet of sufiicient area to overlie the opening definedby collar 27. Closure 28 is rigidly secured to a member 29 mounted forfree rotation on a pin or shaft 30 which in turn is mounted in anysuitable means such as the walls of a casing 37. Member 29 includes alever arm 31, the latter having its outer end pivotally connected to arod 32. Rod 32 is in turn pivotally connected to the extending end 33 ofthe core member of a pull type solenoid 34.

Casing 37, which is airtight or substantially airtight except for theopenings hereinafter referred to, surrounds collar 27 and its lateraland top and bottom walls are suitably seamed, as by welding, to theannular wall of chamber 10. The casing is of sufiicient size to permitthe swinging of closure 28 between a position in which it is in contactwith the collar 27 to close port 25, the dotted line position of theclosure, and an open position, the full line position of the closure(FIG. 1). Casing 37 also includes an upward extension enclosing theelements 30 and 31 and a portion of rod 32. The upward extension isprovided with a port 38 through which rod 32 projects. A closure member39 for port 38 is carried by rod 32 the closure member including a disk40 having a collar 41 secured as by a set screw 42 to the shaft 32. Adisk or ring 43 of rubber or other suitable gasketing material issecured to disk 40 to provide a substantially airtight seal with thechamber walls when closure 39 is in port closing position. As will beobserved closure 39 is so adjusted on shaft 32 that when member 29 isrotated to move closure 28 to its open position, closure 39 is moved toits port closing position and vice versa.

A tube 44 is connected into an opening in the lower wall of casing 37and leads to and is in communication with the intake side of a suctionfan 45 adapted for continuous operation as by motor 46. For purposes ofconvenience in description and claiming the tube 44 and casing 37 willhereinafter sometimes be referred to together as a conduit.

Solenoids 20 and 34 are connected into an electrical circuit to beenergized in timed relationship to the operation of the knittingmachine. For this purpose the solenoids are connected by leads 47 and 48respectively to a main line or power source 49 through normally openmicroswitches 50 and 51 respectively. Microswitches 50 and 51 aresupported in a suitable manner, not shown, adjacent a conventionalpattern drum or other pattern means 52 of the knitting machine thepattern means carrying a plurality of annular rows of buttons forinitiating various movements of the machine. Annular rows of buttons 55and 56 are assigned to the microswitches 50 and 51, respectively. Eachof the switches 50 and 51 includes a spring biased contact member, 53and 54 respectively, adapted when depressed against the action of itsspring to close its switch. Each of the contact members has a rollerpositioned to ride up on the buttons 55 or 56 making up the row oppositeit. Drum 52 is rotated at intervals by any conventional means, notshown, to move the buttons into and out of contact with the contactmembers to close the switches for predetermined intervals measured bythe circumferential extent of the buttons and to then permit theswitches to open.

In the operation of the knitting machine described above motor 46 iscontinuously operated to drive the suction fan 45. Assuming that at thestart of the operation the pattern drum 52 is positioned so that theswitches 50 and 51 are open and the solenoids de-energized, the suctionforce will cause port closures 28 and 39 to move to open and closedpositions, respectively. Also door 11 will be maintained in closedposition by counterweight 22. As a consequence an air stream is drawnthrough the funnel mouth 7 of the tube 6, through the tube andcollection chamber and to the fan. During this operation the fabricbeing formed by the knitting instrumentalities of the knitting machineenters mouth 7 and extending into tube 6 is entrained and tensioned bythe air stream. When the knitting is completed and the last course offabric is "pressed off the needles the air stream then serves to deliverthe completed stocking to the collection chamber 10. As previouslypointed out it has been found desirable, if not essential, at certaintimes to interrupt the air stream to relieve the tension on the fabricparticularly in the knitting of womens hosiery.

Thus if the air stream continues during the knitting of the make-upcourses, namely those courses formed by the needles and transfer bits,the movement of air around the needles and bits provides a disruptinginfluence. Again during the reciprocating knitting of the heel pocketthe constant tensioning of the fabric by the air stream creates anundesirable pull on the loops held by the idled needles tending toelongate them. Also after completion of the stocking and the pressingoff of the fabric loops from the needles, if the air stream is inoperation it immediately Whisks the stocking through the tube and towardthe collection chamber this occurring before the thread cutter has anopportunity to sever the yarn with the result that a number of coursesof the loopers round may be raveled back. The instant inventioneliminates these problems in that it permits the interruption of the airstream and its tensioning effect on the stockings during these periodsor any other period in which such interruptions are found desirable.Thus by proper arrangement of the buttons on the pattern means solenoid34 may be energized at any appropriate point in the knitting cycle tomove rod 32 to the right as shown in FIG. 1 to move closure 39 away fromthe port 38 and to swing closure 28 against collar 27 whereby the airstream through the tube 6 and chamber 10 is interrupted and air is drawnthrough port 38. As soon as the solenoid is deenergized the air drawn bythe fan serves to swing closure 28 to open position and tosimultaneously move closure 39 to closed position whereby the air isagain drawn through the complete system. During all such interruption ofthe air stream door 12 is held in closed position by the counterweightexcept the one occasion in each knitting cycle when the fabric isdeposited in the collection chamber and is to be delivered therefrom toa tray 57. On this occasion the air stream is briefly interrupted asdescribed above and substantially simultaneously therewith the solenoid20 is energized by a properly placed button on the pattern means to opendoor 11 and allow the stocking to drop out of the chamber into the tray57.

Having thus described my invention in full detail it will be understoodthat various changes and modifications may be made therein withoutdeparting from the scope of the accompanying claims.

I claim:

1. ln a suction take-off for a circular knitting machine, a tube adaptedto receive fabric formed on the machine leading to and in communicationwith a collection chamher, a door in said chamber, and a conduit leadingfrom said chamber to a suction means whereby a flow of air is createdthrough said tube and collection chamber, the improvement comprisingmeans for interrupting said flow of air through said tube and chamber,and means for simultaneously opening said conduit to the atmospherewhile maintaining said door in closed position.

2. In a suction take-oft device for a circular knitting machine, a tubeadapted to receive fabric formed onthe machine leading to and incommunication with a collection chamber, a door in said chamber, and aconduit leading from said chamber to a suction means whereby a flow ofair is created through said tube and chamber, the improvement comprisinga port in said chamber providing communication between said chamber andsaid conduit, a second port in said conduit providing communicationbetween said conduit and the atmosphere, and means for simultaneouslyclosing said first port and opening said second port while maintainingsaid door in closed position.

3. In a suction take-off for a circular knitting machine,

a tube adapted to receive fabric formed on the machine leading to and incommunication with a collection chamber, a door in said chamber and aconduit leading from said chamber to a suction means whereby a fiow ofair is created through said tube and chamber, the improvement comprisinga port in said chamber providing communication between said chamber andsaid conduit, a second port providing communication between said conduitand the atmosphere, and pattern controlled means for automaticallyclosing said first port and opening said second port at predeterminedtimes in the operation of the knitting machine while maintaining saiddoor in closed position at certain of said times. 4. A device as claimedin claim 3 in which said means for simultaneously closing said firstport and opening said second port comprise solenoid operated closuresfor said ports and said controlling means comprises an electricalcircuit and a pattern operated switch for opening and closing saidcircuit.

5. In a suction take-off for a circular knitting machine, a tube adaptedto receive fabric formed on the machine leading to and in communicationwith a collection chamber, a door in said chamber, and a conduit leadingfrom said chamber to a suction means whereby a flow of air is createdthrough said tube and chamber, the improvement comprising means fornormally maintaining said door in a closed position, means for openingsaid door, a port in said chamber providing communication between saidchamber and said conduit, a port in said conduit providing communicationbetween the conduit and the atmosphere, and pattern controlled means forat times closing said first port and opening said second port while saiddoor is maintained in closed position and at another time substantiallysimultaneously with the operation of said door opening means.

6. In a suction take-off for a circular knitting machine, a tube adaptedto receive fabric formed on the machine leading to and in communicationwith a collection chamber, a door for said chamber and a conduit leadingfrom said chamber to a suction means whereby a flow of air is createdthrough said tube and chamber, the improvement comprising means fornormally maintaining said door in closed position, means for openingsaid door, a port in said chamber providing communication between saidchamber and said conduit, a closure for said port normally maintained inopen position, a port in said conduit providing communication betweenthe port and the atmosphere, a closure for said second port normallymaintained in closed position, means for operating said port closures,and pattern controlled means for energizing said port closure operatingmeans to close said first port and simultaneously open said second portand at times to energize said door opening means to open said doorsubstantially simultaneously with said operation of said closureoperating means.

7. A device as claimed in claim 6 in which said door opening and closureoperating means comprise solenoids and controlling means thereforcomprising electrical circuits including switches operated by a patterndevice.

References Cited in the file of this patent UNITED STATES PATENTS961,364 Maclaren June 14, 1910 FOREIGN PATENTS 202,394 Australia July 5,1956 801,449 Great Britain Sept. 17, 1958 1,183,041 France Jan. 26, 1959

